LCC Central Power vs Wall Warts?

[dcarrell8]

LCC is meant to replace things like LocoNet, XpressNet, C/MRI, or NCE Cab Bus.

Just curious but how can LCC replace LocoNet?

~ Dennis

[jagged ben]

Just curious but how can LCC replace LocoNet?

~ Dennis

The simple, technical answer: it just does.  It's an alternative architecture for communicating between various components that handle signals, detection, and so forth. 

Of course, you've got to have LCC compatible hardware to use it.  RR-Cirkits has some available, I'm not aware of any others right now but I also haven't looked.

The advantages of LCC, like that of any open standard, would be that it would allow manufacturers to compete on the open market in designing any particular type of product (say, a signal driver) without having to pay licensing fees to some other company (e.g. Digitrax in the case of Loconet), and customers would not be essentially coerced into using one company's products for all their purposes because otherwise they'd need to make multiple different communication systems talk to each other.  So if you like one company's detector and another's signal driver and another's turnout controller, you can pick as you like and they'd all talk to each other.   This is the same idea behind the DCC standard, btw, but LCC is supposed to address some practical shortcomings that DCC has as it relates to controlling these types of things.

I think all the manufacturers would stand to gain from LCC except maybe Digitrax because I gather they would lose out on licensing fees they are currently collecting for Loconet.  Digitrax had come the closest to a de-facto standard with Loconet, so I think they might be making real money off of it whereas I don't think others are (in the US at least).  That's not necessarily good for the modeler constructing a layout, particularly if they don't like Digitrax for some or all applications.  My impression is that Dick Bronson (RR-Cirkits) has been one of the biggest forces behind LCC because he'd be better off not having to license Loconet from Digitrax as he did with past products.  You'll notice his past products were all Loconet compatible and now he is transitioning those to LCC. 

[dcarrell8]

The simple, technical answer: it just does.  It's an alternative architecture for communicating between various components that handle signals, detection, and so forth. 

Of course, you've got to have LCC compatible hardware to use it.  RR-Cirkits has some available, I'm not aware of any others right now but I also haven't looked.

The advantages of LCC, like that of any open standard, would be that it would allow manufacturers to compete on the open market in designing any particular type of product (say, a signal driver) without having to pay licensing fees to some other company (e.g. Digitrax in the case of Loconet), and customers would not be essentially coerced into using one company's products for all their purposes because otherwise they'd need to make multiple different communication systems talk to each other.  So if you like one company's detector and another's signal driver and another's turnout controller, you can pick as you like and they'd all talk to each other.   This is the same idea behind the DCC standard, btw, but LCC is supposed to address some practical shortcomings that DCC has as it relates to controlling these types of things.

I think all the manufacturers would stand to gain from LCC except maybe Digitrax because I gather they would lose out on licensing fees they are currently collecting for Loconet.  Digitrax had come the closest to a de-facto standard with Loconet, so I think they might be making real money off of it whereas I don't think others are (in the US at least).  That's not necessarily good for the modeler constructing a layout, particularly if they don't like Digitrax for some or all applications.  My impression is that Dick Bronson (RR-Cirkits) has been one of the biggest forces behind LCC because he'd be better off not having to license Loconet from Digitrax as he did with past products.  You'll notice his past products were all Loconet compatible and now he is transitioning those to LCC.

Thanks for the great answer, it makes perfect sense. 

[dpharris]

Hi -

I am very involved with OpenLCB / LCC, so if you have any questions, I can probably help. 

LCC is similar to Loconet, in that it is a peer-to-peer accessory bus, , with each node being able to talk to any other node, and is meant to supplement your traction system (DC, DCC, etc.).  It is designed with a bigger world view, it is designed to run over many transports, such as CAN, ethernet, Wifi, etc., and is generally both more flexible and faster than Loconet.  Each LCC node also contains its own description and its configuration, which is useful, and has a unique ID.   

David

[craigolio1]

Is anyone that uses high amp DC power supplies and multiple wire sizes doing any fusing?

I used to work in car audio and car batteries can produce a massive amount of instantaneous current. We would run main power wires in the 4-000awg range and those would be fused somewhere below the max current capacity of those cables, but higher than the max current draw of the system.

We would then run those into fused distribution blocks and go out into smaller awg wire runs for individual components or smaller distribution circuits and those were all
Fused based on the wire size as well.

So from a model RR perspective, let’s say we had a 5a power supply for all of our DCC stuff SMD we ran 14awg as a bus. It would be prudent to fuse that power supply. But then if we were taking off runs of 24awg wire to individual items , that 24awg may be so small that it could heat up in a short situation and be a danger prior to the main fuse blowing, so it would be prudent to fuse that distribution point with a value of what ever that wire can handle.

I know this is on a really small scale. I don’t even know if it’s a danger in the ranges that we work. Just food for thought.

Craig

[peteski]

I know this is on a really small scale. I don’t even know if it’s a danger in the ranges that we work. Just food for thought.

Craig

Sure, small scale, but the voltage times current equals power, and high power can heat up or even melt small gauge wires. We experience that even with DCC where the small gauge wires from the trucks can heat up melting the insulation, or the metal truck side-frame pickups can heat up and melt the plastic sideframes.

Under the layout such thermal events could cause fire. When playing with high-power low-voltage supplies it is prudent to practice safety (like using fuses).

[craigolio1]

Sure, small scale, but the voltage times current equals power, and high power can heat up or even melt small gauge wires. We experience that even with DCC where the small gauge wires from the trucks can heat up melting the insulation, or the metal truck side-frame pickups can heat up and melt the plastic sideframes.

Under the layout such thermal events could cause fire. When playing with high-power low-voltage supplies it is prudent to practice safety (like using fuses).

That’s kind of what I was thinking. I’ve never done any of the calculations but surely it must be worth fusing out DC accessory busses

[railnerd]

That’s kind of what I was thinking. I’ve never done any of the calculations but surely it must be worth fusing out DC accessory busses

Before lockdown, we recently needed to add power regulation and fuse protection to our accessory bus at my HO club.  We had a member who went on a "lighting kick" and ended up adding several amps of power draw to our DCC accessory bus over the span of a few months.

-Dave

[jagged ben]

Is anyone that uses high amp DC power supplies and multiple wire sizes doing any fusing?

I used to work in car audio and car batteries can produce a massive amount of instantaneous current. We would run main power wires in the 4-000awg range and those would be fused somewhere below the max current capacity of those cables, but higher than the max current draw of the system.

We would then run those into fused distribution blocks and go out into smaller awg wire runs for individual components or smaller distribution circuits and those were all
Fused based on the wire size as well.

So from a model RR perspective, let’s say we had a 5a power supply for all of our DCC stuff SMD we ran 14awg as a bus. It would be prudent to fuse that power supply. But then if we were taking off runs of 24awg wire to individual items , that 24awg may be so small that it could heat up in a short situation and be a danger prior to the main fuse blowing, so it would be prudent to fuse that distribution point with a value of what ever that wire can handle.

I know this is on a really small scale. I don’t even know if it’s a danger in the ranges that we work. Just food for thought.

Craig

For the most part I would say ... nah.

Frankly we shouldn't be using power supplies that can deliver that many amps.   If we have too much draw then we should add more separate power supplies.  They should be power limited supplies, i.e. their internal design acts like a fuse and just shuts down or drops the voltage to next to nothing if you try to draw too much power.  You should never use anything like a car battery to power your layout. 

I mean, if you have a 12V or 24V DC supply that can deliver 5A max, and you run everything on a 14awg bus, then fusing at the power supply isn't doing anything useful.  The supply shouldn't be able to deliver enough power to damage the 14awg wire.  So what would you fuse it at?  If you have a 5A supply you should be able to use up to about 5A.   And if you are expanding and you find that all your draw on the bus is getting to be over 5A ...  then you should not swap out the power supply for a bigger one.  You should cut your bus in two somewhere, and feed the separated section with a second 5A power supply.

Now, possibly one could argue that if you have little 24awg taps to the bus for all your devices then you should fuse all those little taps.  But again ... nah.  24awg is going to fine with just about anything your 5A power supply can throw at it.  Now a dead short may heat up right at the short.  There's nothing that fuses are going to do about that.  So just don't make shorts.  Don't leave stuff hooked up if it's not working and you haven't tested why not.  Turn off the layout power when your not staying in the room.  Have a fire extinguisher about.  Those are realistic measures.  It's possible you could start a fire but you'll likely smell it very early.  Life is life.

In summary... Stick with small power supplies, like max 5A.  Stick with wire sizes that are bigger than 24awg for this stuff.  If you need more power, separate stuff into districts. 
 

[kwledbetter]

I fuse everything either physically or through software.  I agree much safer to break things into districts but that's not always possible but even huge layouts rarely need more than 5A.  I have seen a 10A garden layout but that was also before LEDs etc.

Also as an LCC convert let me say why I chose it

1)  generally separating your DCC bus from your layout control bus is a good idea and makes things scalable and less trouble.

2)  in my opinion loconet, Merg CBUS, CMRI, LCC are honestly realistically equivelant. Of course there are differences but they all work and well.  I chose LCC for a couple reasons.  It's open source so that eliminates Loconet.  I wanted an NMRA standard so that somewhat eliminates  Merg cbus (though I am a merg member and have a lot of merg designedelectronics). 

3)  I despise that we even have to have this conversation.   I wish long ago like DCC this would have grown more in popularity where all these options didn't exist.  They all work but many are difficult to learn(including LCC) and have little to no commercially available hardware so you have to piecemeal  a lot yourself.  LCC has some.  Loconet has the most but is also the most proprietary and dependent on one company.  So having said all that I went LCC as I feel I wont regret that a decade down the road but it really depends how much you are willing to learn and do yourself and also how big and complex the layout is.  If it's small a DCC only bus with accessory decoders will do everything you need.  If large and complex than you'll have to pick and get in bed with digitrax,  choose an alternative that will likely always be on the fringe so to speak with no real commercial support (arduino, cbus, cmri, etc)  or take a bet on LCC and hope it becomes more a standard simular to DCC eventually.

[dpharris]

Ok gentlemen, get out your crayons you might need to draw me some pictures.

I am trying to understand exactly how to power my LCC system.  I had planed on using an ATX central power supply from an old computer.  I have four of these and I was looking at incorporating all of them into my large layout. 

Dick Bronson and others on the LCC group have suggested that this is not a good idea because the Signal grounds take different paths from board to board, and thus DCC signals can introduce noise shared in the same circuitry. 

This is how Dick does it:  "I personally use a 15V 5A central power supply to power my LCC network via Power Points. I also use the same power lines to supply I/O boards. The key difference is that the local I/O boards have optical isolation which effectively prevents any power ground line from connecting to any signal ground line. I.e. no way for the ground to connect over two different paths."

I'm hoping someone here can decipher things for me.
1.) Power points - does this simply mean warts at separate plug-in sockets?
2.) Same power lines - so create a buss from the 15v 5A power supply?
3.) Optical isolation - not sure I understand what this means in terms of hardware.

1.  PowerPoint refers to RRCirkits' product: https://www.rr-cirkits.com/description/LCC-Power-Point-flyer.pdf
    This accepts power in, and distributes 500 mA to each of its LCC connectors. 
   
      Power supply----------------+---------------+--------------+----------
                                  PP              PP             PP
                                  ||              ||             ||
                  ==node==node====++==node==node==++===node======++===node===   <--LCC
   

2. Yes, feed the 15V to each of the PowerPoints, and they distribute it to the LCC bus in a controlled way.  The LCC-connectors on the PowerPoint pass-through the LCC bus lines, but separate the power lines. 

3. It prevents ground-loops and other 'nasties'.  The optical isolation is built into the othe RRCirkit products, like the LCC-Buffer-USB (https://www.rr-cirkits.com/description/LCC-usb-flyer.pdf) which prevents interactions with the ground of the connected computer.   

Does that help?

David